Dunkirk Excelsior EXB Series - Manual (Page 58)

58
IF YOUR SYSTEM IS NOT HEATING OR NOT GIVING ENOUGH HEAT . . .
POSSIBLE CAUSE WHAT TO DO
Thermostat is not set correctly Reset thermostat
Burner is not operating properly Adjust burner per instructions.
No electric power to boiler
Check over-current protection. Check to be sure electric power supply cir-
cuit is “ON”. There may be as many as 3 safety shut-off switches installed.
Look for a red plate which may be on the service switch.
Controls out of adjustment Reset according to instructions.
Circulating pump not running
Check over-current protection. Check relay operation. Check power to
circulator.
Poor electrical contact Check all control terminals and wire joints.
Chimney flue is blocked Have the chimney professionally cleaned.
RELIEF VALVE LEAKING . . .
POSSIBLE CAUSE WHAT TO DO
Corrosion and/or deposits on
seat.
Open valve manually. Allow water to run and clear valve seat.
Water logged expansion tank Drain tank, follow instructions to provide air buffer.
HAVE YOUR SERVICE TECHNICIAN CHECK ANY PROBLEM YOU ARE UNABLE TO CORRECT.
LIMIT CONTROL TROUBLESHOOTING GUIDE
System Condition Diagnostic Condition Check Action
Boiler is cold,
house is cold.
Display off 120 VAC system power Turn system power on
Display on 24 VAC T-T No 24 V; replace control
24 V present; disconnect
thermostat, short T-T
Boiler starts, check wiring and thermostat
120 VAC at B1-B2 • If no, replace
• If yes, check burner and wiring
Low Water status light • If illuminated, find and repair water
leak(s).
Boiler is hot,
house is cold.
Display on 120 VAC at C1-C2 • 120 vac at C1-C2, check wiring to
pump
• Wiring OK, is pump running?
• If not, replace pump.
• If pump is running, check for trapped
air or closed zone valves.
Burner will not
turn off.
Display On Burner wired incorrectly. L1
(black) and Limit (red) are
reversed. See wiring diagram
for installed burner.
Re-Wire burner.
20 - TROUBLESHOOTING